Iowa CDL Requirements (2026): Age, the Permit, the Knowledge Test and Fees

1. Study the Iowa CDL manual and pass the knowledge tests for the class you want. Everyone takes general knowledge. Class A drivers also take combination vehicles, and air brakes if the truck has air brakes.
2. Get your commercial learner's permit (CLP). The permit fee is $12.
3. Hold the permit at least 14 days while you practice with a licensed CDL driver.
4. Finish entry-level driver training (ELDT) with a provider on the FMCSA Training Provider Registry, if this is your first Class A or Class B CDL or you are moving up from Class B to Class A.
5. Pass the skills test: the vehicle inspection, basic control and the road test. Where to take it: Select Iowa DOT and County Treasurer locations by appointment, plus third-party testers trained and authorized by the Iowa DOT (many are community colleges). You provide a registered vehicle that represents the class you want.

You need at least 80 percent right on each knowledge test.

Iowa lists the general knowledge test as 50 questions with 10 allowed to miss, so you need 40 correct (80 percent). Other tests: combination 20 (miss 4), air brake 25 (miss 5), hazmat 30 (miss 6), and a 25-question Iowa operator test if it applies. Knowledge tests are given at DOT and County Treasurer locations by appointment.

Practice with the free CDL test below: 10 questions at a time from the general knowledge section, each with the answer explained.

The CLP is $12 and must be added to an existing license; it is valid one year. A Class A, B, or C commercial license costs $8 per year of the license term, so a full 8-year CDL is $64 (licenses for people 78 and older run two years). Iowa does not list a separate knowledge or skills test fee on the pages checked; third-party testers (community colleges and private sites) may charge their own fee.

You must be 18 to drive a commercial vehicle only inside Iowa and 21 to drive across state lines.

Iowa states the 18 minimum for a CDL. The 21 minimum for interstate driving is the federal rule (49 CFR 391.11).

Federal rules set 21 as the minimum age to drive a commercial vehicle across state lines.

Hold your CLP at least 14 days before you take the skills test. The permit is good for 1 year.

Since February 7, 2022, federal rules require entry-level driver training from a provider on the FMCSA Training Provider Registry before the skills test if you are getting a Class A or Class B CDL for the first time, moving up from Class B to Class A, or adding a school bus or passenger endorsement for the first time. For a first hazardous materials endorsement, the training comes before the hazmat knowledge test.

The Iowa DOT confirms ELDT completion on the FMCSA Training Provider Registry before giving CDL tests. The Iowa DOT, Iowa Workforce Development, and the Iowa Department of Education point applicants to funding for ELDT or full CDL training at Iowa providers, including GAP Tuition Assistance and PACE through community colleges and WIOA Title I through IowaWORKS centers.

The skills test has three parts: the vehicle inspection, basic vehicle control and the road test. Our CDL pre-trip inspection checklist walks through the inspection.

Where: Select Iowa DOT and County Treasurer locations by appointment, plus third-party testers trained and authorized by the Iowa DOT (many are community colleges). You provide a registered vehicle that represents the class you want.

If you fail: If you fail the air brake check or the pre-trip inspection, you must book another appointment to retest, which may be two or three weeks out.

Iowa skills test details.

Self-certify the kind of driving you do every time you receive a CDL product (with the examiner or on the online Certification for Commercial Driver's License form). Non-excepted interstate drivers must have a medical examiner's certificate on file; since Oct. 23, 2025 the National Registry examiner submits it electronically. Intrastate categories add a K restriction.

Many trucking companies hire drivers with a new CDL and train them with an experienced driver. Look at the CDL driver openings near you, and get your resume written for each one. The CDL driver resume and CDL interview questions pages help with the rest.

Need help paying for CDL school? WIOA training money can cover it for people who qualify: WIOA CDL training. Every state is on the CDL requirements by state page.

1. How much tread depth do the front tires need, at a minimum, in every major groove?
   Answer: 4/32 inch. Front tires need at least 4/32 inch of tread in every major groove. The other tires need at least 2/32 inch.
2. You are hauling cargo. When must you first check how it is tied down after you start the trip?
   Answer: Within the first 50 miles. Check the cargo and its tie-downs within the first 50 miles of the trip, then keep checking it as you go.
3. After that first check, how often must you check how the cargo is tied down?
   Answer: Every 150 miles or every 3 hours, whichever comes first. After the first 50 miles, check again every 150 miles or every 3 hours, whichever comes first, and after every break.
4. A tire on your truck was just changed. What should you do?
   Answer: Stop a short while later and check that the wheel nuts are still tight. Wheel nuts can loosen after a tire change. Stop a short while later and recheck that they are tight.
5. How far ahead do most good drivers look?
   Answer: 12 to 15 seconds ahead. Look 12 to 15 seconds ahead, so you have time to slow down or change lanes before you reach a problem.
6. At highway speed, about how far is 12 to 15 seconds ahead?
   Answer: About a quarter of a mile. At highway speeds, 12 to 15 seconds is about a quarter of a mile. In town it is about one block.
7. You drive a 40-foot truck at under 40 mph. How much following distance should you keep?
   Answer: 4 seconds. Keep 1 second for every 10 feet of vehicle length below 40 mph. A 40-foot truck needs 4 seconds.
8. You drive a 50-foot truck at over 40 mph. How much following distance should you keep?
   Answer: 6 seconds. One second per 10 feet gives 5 seconds. Above 40 mph, add 1 more second, for 6 seconds.
9. In ideal conditions at 55 mph, about how far will your truck travel before it stops, counting the time to see, react and brake?
   Answer: About 419 feet. The manual adds about 142 feet to recognize the hazard, 61 feet to react and 216 feet to brake, for at least 419 feet.
10. If you double your speed from 20 mph to 40 mph, what happens to your braking distance?
    Answer: It becomes about 4 times longer. Doubling your speed makes the braking distance and the force of a crash about 4 times greater.
11. How much should you slow down on a wet road?
    Answer: Slow down by about one-third. Wet roads can double your stopping distance. Slow down by about one-third, for example from 55 to about 35 mph.
12. How much should you slow down on packed snow?
    Answer: By half or more. On packed snow, cut your speed by half or more. On ice, slow to a crawl and stop as soon as it is safe.
13. When the temperature drops near freezing, which part of the road usually freezes first?
    Answer: Bridges. Bridges freeze before the rest of the road. Be extra careful on them when it is close to 32 degrees.
14. Your truck starts to hydroplane on standing water. What should you do?
    Answer: Take your foot off the accelerator and push in the clutch. Release the accelerator and push in the clutch so the wheels turn freely. Do not use the brakes to slow down.
15. What is the safe way to take a curve?
    Answer: Slow to a safe speed before you enter the curve. Slow down before the curve. Braking in a curve can lock the wheels and cause a skid, and a tall truck can roll over even at the posted curve speed.
16. You are about to go down a long, steep grade. When should you shift to a low gear?
    Answer: Before you start down the grade. Shift down before the grade. Once speed builds up you may not be able to get into a lower gear, and you can lose all engine braking.
17. Your safe speed on a downgrade is 40 mph. You are in the right low gear and reach 40 mph. What should you do?
    Answer: Brake firmly until you slow to about 35 mph, then let off the brakes. Brake hard enough to feel a clear slowdown to about 5 mph under your safe speed, then release. Repeat each time you reach the safe speed.
18. What can happen if some of your brakes are out of adjustment?
    Answer: The other brakes do more work, overheat and can fade. Brakes out of adjustment stop doing their share. The others overheat and fade, so check adjustment often.
19. Why does an empty truck need more distance to stop than a loaded one?
    Answer: An empty truck has less traction. Brakes, tires and springs work best when the truck is loaded. An empty truck has less traction, so it needs more room to stop.
20. You must stop on the shoulder of a road. How soon must your warning triangles be out?
    Answer: Within 10 minutes. Turn on your four-way flashers and put out your warning devices within 10 minutes of stopping.
21. You stop on a divided highway. Where do the three warning triangles go?
    Answer: 10, 100 and 200 feet toward the approaching traffic. On a one-way or divided highway, place them 10 feet, 100 feet and 200 feet toward the traffic coming at you.
22. You stop on a two-lane road with traffic in both directions. Where do the triangles go?
    Answer: One within 10 feet of a front or rear corner, one 100 feet behind and one 100 feet ahead. On a two-way road, mark the truck within 10 feet of a front or rear corner, then put one 100 feet behind and one 100 feet ahead.
23. You must stop at a railroad crossing that has no white stop line. Where do you stop?
    Answer: No closer than 15 feet and no more than 50 feet from the nearest rail. With no stop line, stop no closer than 15 feet and no farther than 50 feet from the nearest rail.
24. About how long does a typical tractor-trailer take to clear a single railroad track?
    Answer: At least 14 seconds. A typical tractor-trailer needs at least 14 seconds to clear one track and more than 15 seconds for two. Be sure you can get all the way across before you start.
25. Your truck gets stuck on the railroad tracks. What should you do?
    Answer: Get out, move away from the tracks, and call the number posted at the crossing or 911. Get out and away from the tracks. Call the emergency number on the crossing sign or 911, and give the crossing's DOT number if it is posted.
26. What is "controlled braking"?
    Answer: Braking as hard as you can without locking the wheels. In controlled braking you brake as hard as you can without locking the wheels, and keep steering movements very small.
27. You must steer quickly to miss a crash. What should you avoid?
    Answer: Braking while you are turning. Do not brake while you turn. It is easy to lock the wheels and skid out of control.
28. A front tire blows out. What should you do first?
    Answer: Hold the steering wheel firmly and stay off the brake until the truck slows down. Hold the wheel firmly with both hands. Stay off the brake until the truck slows, then brake gently and pull off the road.
29. The yellow ABS malfunction lamp stays on while you drive. What does it mean?
    Answer: You may have lost antilock braking, but you still have regular brakes. Drive normally and get it fixed soon. A lamp that stays on means ABS may not be working on one or more wheels. Your regular brakes still work, so drive normally and have it serviced soon.
30. The rear drive wheels lock up and start to skid. What should you do?
    Answer: Stop braking, then counter-steer. Let off the brakes so the rear wheels roll again, then counter-steer as the truck comes back on course.
31. What causes most front-wheel skids?
    Answer: Driving too fast for conditions. Most front-wheel skids come from driving too fast for conditions. Worn front tires and too little weight on the front axle also cause them.
32. You are at an accident scene. What is the first thing to do?
    Answer: Protect the area so another crash does not happen there. First keep another crash from happening: move your truck off the road if you can, turn on your flashers and put out triangles.
33. Your engine catches fire. What should you do?
    Answer: Turn off the engine and avoid opening the hood if you can. Turn off the engine and do not open the hood if you can avoid it. Spray through the vents (louvers), the radiator or from underneath, and never pull into a service station.
34. There is a fire in the cargo of your closed van trailer. What should you do with the doors?
    Answer: Keep them shut. Keep the doors shut. Opening them feeds the fire air and can make it burn very fast, especially with hazardous cargo.
35. Where do you aim a fire extinguisher?
    Answer: At the base or source of the fire. Aim at the base of the fire, stay as far back as you can, and stand upwind so the wind carries the spray to the fire.
36. It is illegal to drive a commercial vehicle with a blood alcohol concentration of:
    Answer: .04% or more. At .04% or more it is illegal, and a first offense costs your CDL for at least one year. Any detectable alcohol under .04% still puts you out of service for 24 hours.
37. What sobers a person up after drinking?
    Answer: Only time. The liver clears alcohol at a fixed rate, about one-third of an ounce an hour. Only time works.
38. Which use of a phone is allowed while you drive a commercial vehicle?
    Answer: Talking on a hands-free phone that is close to you. You may only use a hands-free phone that is close to you. Holding it, dialing with more than one button or reaching for it is not allowed, except to call for help in an emergency.
39. How many tie-downs does cargo need?
    Answer: At least one for every 10 feet of cargo, and never fewer than two. Use at least one tie-down for every 10 feet of cargo. Even small cargo needs at least two.
40. How should you load heavy cargo?
    Answer: As low as possible, with the heaviest parts under the lightest. A high center of gravity makes rollover more likely. Keep cargo low and put the heaviest parts under the lightest.

• Iowa Department of Transportation (Iowa DOT), Motor Vehicle Division
• Iowa CDL manual
• Iowa: get cdl (iowadot.gov)
• Iowa: cdl testing (iowadot.gov)
• Iowa: commercial learner permits clp (iowadot.gov)
• Iowa: medical cards certification (iowadot.gov)
• Iowa: entry level driver training (iowadot.gov)
• Iowa: fees (iowadot.gov)
• Iowa: testing locations (iowadot.gov)
• Federal rule: faqs (www.fmcsa.dot.gov)
• FMCSA: how to get a commercial driver's license